[SYCL][NFC] Code clean up (phase 5) revealed by self build. (#2907)

Author: zahiraam

clang/include/clang/Sema/Sema.h

@@ -410,9 +410,6 @@ class SYCLIntegrationHeader {
   /// integration header emission time.
   llvm::SmallVector<SpecConstID, 4> SpecConsts;
 
-  /// Used for emitting diagnostics.
-  DiagnosticsEngine &Diag;
-
   /// Whether header is generated with unnamed lambda support
   bool UnnamedLambdaSupport;
 

clang/lib/Driver/Driver.cpp

@@ -5116,7 +5116,7 @@ void Driver::BuildActions(Compilation &C, DerivedArgList &Args,
     OffloadBuilder.addDeviceDependencesToHostAction(
         Current, InputArg, phases::Link, PL.back(), PL);
   };
-  for (const StringRef &LA : LinkArgs) {
+  for (StringRef LA : LinkArgs) {
     // At this point, we will process the archives for FPGA AOCO and individual
     // archive unbundling for Windows.
     if (!isStaticArchiveFile(LA))

clang/lib/Sema/SemaSYCL.cpp

@@ -3988,7 +3988,7 @@ void SYCLIntegrationHeader::setCallsThisItem(bool B) {
 SYCLIntegrationHeader::SYCLIntegrationHeader(DiagnosticsEngine &_Diag,
                                              bool _UnnamedLambdaSupport,
                                              Sema &_S)
-    : Diag(_Diag), UnnamedLambdaSupport(_UnnamedLambdaSupport), S(_S) {}
+    : UnnamedLambdaSupport(_UnnamedLambdaSupport), S(_S) {}
 
 // -----------------------------------------------------------------------------
 // Utility class methods